file.haml

%fieldset.common-form.standard-form
  = form_for @customer, :html => { :multipart => true } do |f|
    = f.error_messages
    %table{:border => "0"}
      %tr
        %th= f.label :name
        %td= f.text_field :name
      %tr
        %th= f.label :street
        %td= f.text_field :street
      %tr
        %th= f.label :city
        %td= f.text_field :city
      %tr
        %th= f.label :state
        %td= f.text_field :state
      %tr
        %th= f.label :zip
        %td= f.text_field :zip
      %tr
        %th= f.label :logo
        %td
          = f.file_field :logo
          = image_tag @customer.logo.url(:thumb)
      %tr
        %th
        %td= f.submit 'Update'

file.html.erb

<fieldset class="common-form standard-form">
  <%= form_for @customer, :html => { :multipart => true } do |f| %>
    <%= f.error_messages %>
    <table border="0">
      <tr><th><%= f.label :name %></th><td><%= f.text_field :name %></td></tr>
      <tr><th><%= f.label :street %></th><td><%= f.text_field :street %></td></tr>
      <tr><th><%= f.label :city %></th><td><%= f.text_field :city %></td></tr>
      <tr><th><%= f.label :state %></th><td><%= f.text_field :state %></td></tr>
      <tr><th><%= f.label :zip %></th><td><%= f.text_field :zip %></td></tr>
      <tr><th><%= f.label :logo %></th><td><%= f.file_field :logo %> <%= image_tag @customer.logo.url(:thumb) %></td></tr>
      <tr><th></th><td><%= f.submit 'Update' %></td></tr>
    </table>
  <% end %>
</fieldset>